The present invention relates generally apparatus for sampling of solid, liquid, and semi-solid bulk materials such as powders, liquids, and gels, and more specifically, to a non-compacting bulk material sampler.
Sampling of bulk mixtures of granular or powdery materials to evaluate the degree of mixing at different locations in a mixing vessel is typically done using a probe or sample xe2x80x9cthiefxe2x80x9d that is inserted in the bulk mixture to remove a representative sample. A typical sample thief comprises a long tubular shell having at least one aperture on a side wall near the lower end of the probe, and a second inner mating tube also having at least one aperture. The aperture in the inner tube can be aligned with the aperture in the outer tube by rotating the inner tube within the outer tube. In operation, the probe is inserted in the bulk mixture to the desired depth with the inner tube and outer tube apertures not aligned. After insertion of the tube to a desired depth, the inner tube is rotated to aligri the two openings, thus allowing bulk material to flow in the opened inner tube. The opening is then closed by again rotating the inner tube, and the probe is removed from the bulk material thus retrieving a sample of the material from a desired point in the mixing vessel. The sample retrieved is then recovered from the probe by re-aligning the inner and outer tube apertures and allowing the sample to fall out into a sample container, from which the sample then can be processed for further analysis or study as needed.
Sampling of bulk materials in a precise, repeatable and reproducible manner has historically been a technical challenge not readily overcome. For example, the mere rotation of the inner tube within the outer tube does not necessarily provide an impetus to draw the sample into the apertures. Thus, shaking or other movement may be required. Furthermore the rotation motion is not easily accomplished with one hand. Sometimes it is desired to use a single sample thief with a number of mating apertures in the inner and outer tubes for taking samples at a number of depths simultaneously. To allow for the rotation between the inner and outer tubes, there is necessarily a certain degree of tolerance between inner and outer tubes. The shaking motion necessary to draw sample into the apertures may also cause some of the sample collected through an upper set of apertures to fall between the inner and outer tubes into the sample collected at a lower set of apertures. This contamination of the sample from one depth with the sample from another may be undesirable.
Samplers are known that are particularly adept at overcoming many of these problems, such as for example, the samplers described in U.S. Pat. Nos. 5,476,017 and 5,703,301, assigned to the common assignee of this invention. These samplers, however, provide compacting of the sample, which is desirable in many applications. In other applications, however, it may be desired not to compact the sample. In still other applications, it may be desirable to have a sampler capable of not only sampling bulk powder or granular material, but also liquid or gelatinous material.
Thus, non-compacting sampling apparatus are still desired that are able to recover predetermined size samples from mixing bulk materials with a high degree of repeatability of the sample size, with minimal disturbance of the bulk material in the sampling vicinity, and with the ability to recover substantially all of the retrieved sample from the sampling apparatus in a format easily amenable to further testing. It is further desirable to provide such apparatus that are maneuverable with one hand and that are adaptable for use in a multitude of applications.
The invention comprises a bulk material sampler comprising an elongated body, a handle, and a shaft assembly. The body has an axis, a first axial bore, and an interior wall; the handle is coaxial with the body axis and has a second axial bore and a finger grip. The bottom end of the handle is connected to the top end of the body. The shaft assembly is supported in the first and second bores coaxial with the body axis. The shaft assembly comprises a tip at the shaft assembly bottom end and a button at the shaft assembly top end. The button is adapted to protrude from the handle top end. The shaft assembly is axially moveable between an actuated position in which the button is maximally depressed within the handle, and a resting position in which the button maximally protrudes from the handle. The comprises means for biasing the shaft in the resting position and a sample collection chamber defined by a portion of the tip and a portion of the body interior wall.
The tip may comprise a sample collection cavity therein, and may be adapted to at least partially protrude from the body bottom end such that the tip maximally protrudes in the actuated position and minimally protrudes in the resting position. The sample collection cavity in the tip may, for example, comprise an annular cutout coaxial with the body axis or a bore hole perpendicular to the body axis.
The tip may be removable from the shaft assembly. A number of tip configurations may be provided, each tailored for particular sampling applications. For example, a tip adapted for bulk powder sampling may comprise a pointed endpiece adapted to protrude from the body even in the resting position. A tip having a plurality of sample collection cavities axially spaced from one another may be adapted for taking multiple samples. A tip adapted for liquid sampling may comprise a groove above the sample collection cavity and an o-ring in the groove. A tip adapted for sampling of gelatinous materials may comprise a blunt bottom end, a groove, and an o-ring in the groove, in which the tip bottom end is adapted to be substantially flush with the body bottom end when the shaft assembly is in the actuated position and maximally receded when the shaft assembly is in the resting position. With the gel-sampling tip attached, the sample collection chamber is defined by the body interior wall between the bottom end of the tip and the bottom end of the body when the shaft is in the resting position.
In one embodiment, the invention comprises a sampler for bulk solid material comprising a first elongated outer sleeve, a second elongated coaxial inner member moveably nestled in the outer sleeve, means for extending an end portion of the inner member from a first axial position within the outer sleeve to a second axial position outside the outer sleeve; and non-compacting means in the inner member end portion for collecting bulk solid material in the end portion when said sampler is inserted in the bulk solid material. The inner member end portion may comprise a cavity at a lower end thereof for collecting bulk solid material when the sampler is inserted in the bulk solid material.